Just this January, LG showed off its highest-resolution displays yet, including an impressive 5.5-inch 1920 x 1080 panel. But progress marches onward, and today the company is announcing a panel with nearly twice as many pixels — 2560 x 1440 — in the same size. The new panel measures the same 5.5 inches diagonally and is just 1.21 millimeters thick, making it (according to LG), not only the most pixel dense smartphone LCD in existence, but also the slimmest. The Quad HD resolution means it has four times the pixels of a 720p panel, not a 1080p one, but it does have a singularly impressive 538ppi and 430 nits of brightness. There’s no word on when the panel could make it into actual products, but it goes to show that the pixel density race isn't slowing down just yet.